Gases and vapors which may be potentially hazardous, contaminative, dangerous or otherwise undesirable, such as propane, water vapor, formaldehyde, methane, carbon monoxide, mercury vapor, ethylene oxide, hydrogen sulfide, and other hazardous gases, are sometimes difficult to detect, especially where they are odorless or present at levels that cannot be smelled, or are masked by other odors. The danger of these hazardous gases is becoming increasingly apparent, especially in industrial plants, mines, environmentally sealed homes and office buildings, recreational and other vehicles and other environments in which people are present for long periods of time. To detect and quantify the concentration of gases, various sensors have been developed which typically include visual detection of color change or measurement of electric properties. However, such sensors require a long reaction time and have low sensitivity. Such hazards are also found in liquid streams.
Furthermore, the existing portable devices for detecting gases such as mercury vapor, water vapor, and formaldehyde are expensive. Accordingly, there is a need for a detection apparatus for sensing and measuring these gases that is easy to fabricate, cost efficient and reliable.